2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * Implementation of the Transmission Control Protocol(TCP).
8 * IPv4 specific functions
13 * linux/ipv4/tcp_input.c
14 * linux/ipv4/tcp_output.c
16 * See tcp.c for author information
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
26 * David S. Miller : New socket lookup architecture.
27 * This code is dedicated to John Dyson.
28 * David S. Miller : Change semantics of established hash,
29 * half is devoted to TIME_WAIT sockets
30 * and the rest go in the other half.
31 * Andi Kleen : Add support for syncookies and fixed
32 * some bugs: ip options weren't passed to
33 * the TCP layer, missed a check for an
35 * Andi Kleen : Implemented fast path mtu discovery.
36 * Fixed many serious bugs in the
37 * request_sock handling and moved
38 * most of it into the af independent code.
39 * Added tail drop and some other bugfixes.
40 * Added new listen semantics.
41 * Mike McLagan : Routing by source
42 * Juan Jose Ciarlante: ip_dynaddr bits
43 * Andi Kleen: various fixes.
44 * Vitaly E. Lavrov : Transparent proxy revived after year
46 * Andi Kleen : Fix new listen.
47 * Andi Kleen : Fix accept error reporting.
48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind
50 * a single port at the same time.
53 #define pr_fmt(fmt) "TCP: " fmt
55 #include <linux/bottom_half.h>
56 #include <linux/types.h>
57 #include <linux/fcntl.h>
58 #include <linux/module.h>
59 #include <linux/random.h>
60 #include <linux/cache.h>
61 #include <linux/jhash.h>
62 #include <linux/init.h>
63 #include <linux/times.h>
64 #include <linux/slab.h>
66 #include <net/net_namespace.h>
68 #include <net/inet_hashtables.h>
70 #include <net/transp_v6.h>
72 #include <net/inet_common.h>
73 #include <net/timewait_sock.h>
75 #include <net/netdma.h>
76 #include <net/secure_seq.h>
77 #include <net/tcp_memcontrol.h>
78 #include <net/busy_poll.h>
80 #include <linux/inet.h>
81 #include <linux/ipv6.h>
82 #include <linux/stddef.h>
83 #include <linux/proc_fs.h>
84 #include <linux/seq_file.h>
86 #include <linux/crypto.h>
87 #include <linux/scatterlist.h>
89 int sysctl_tcp_tw_reuse __read_mostly;
90 int sysctl_tcp_low_latency __read_mostly;
91 EXPORT_SYMBOL(sysctl_tcp_low_latency);
94 #ifdef CONFIG_TCP_MD5SIG
95 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
96 __be32 daddr, __be32 saddr, const struct tcphdr *th);
99 struct inet_hashinfo tcp_hashinfo;
100 EXPORT_SYMBOL(tcp_hashinfo);
102 static __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
104 return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
107 tcp_hdr(skb)->source);
110 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
112 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
113 struct tcp_sock *tp = tcp_sk(sk);
115 /* With PAWS, it is safe from the viewpoint
116 of data integrity. Even without PAWS it is safe provided sequence
117 spaces do not overlap i.e. at data rates <= 80Mbit/sec.
119 Actually, the idea is close to VJ's one, only timestamp cache is
120 held not per host, but per port pair and TW bucket is used as state
123 If TW bucket has been already destroyed we fall back to VJ's scheme
124 and use initial timestamp retrieved from peer table.
126 if (tcptw->tw_ts_recent_stamp &&
127 (twp == NULL || (sysctl_tcp_tw_reuse &&
128 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
129 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
130 if (tp->write_seq == 0)
132 tp->rx_opt.ts_recent = tcptw->tw_ts_recent;
133 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
140 EXPORT_SYMBOL_GPL(tcp_twsk_unique);
142 /* This will initiate an outgoing connection. */
143 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
145 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
146 struct inet_sock *inet = inet_sk(sk);
147 struct tcp_sock *tp = tcp_sk(sk);
148 __be16 orig_sport, orig_dport;
149 __be32 daddr, nexthop;
153 struct ip_options_rcu *inet_opt;
155 if (addr_len < sizeof(struct sockaddr_in))
158 if (usin->sin_family != AF_INET)
159 return -EAFNOSUPPORT;
161 nexthop = daddr = usin->sin_addr.s_addr;
162 inet_opt = rcu_dereference_protected(inet->inet_opt,
163 sock_owned_by_user(sk));
164 if (inet_opt && inet_opt->opt.srr) {
167 nexthop = inet_opt->opt.faddr;
170 orig_sport = inet->inet_sport;
171 orig_dport = usin->sin_port;
172 fl4 = &inet->cork.fl.u.ip4;
173 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
174 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
176 orig_sport, orig_dport, sk);
179 if (err == -ENETUNREACH)
180 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
184 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
189 if (!inet_opt || !inet_opt->opt.srr)
192 if (!inet->inet_saddr)
193 inet->inet_saddr = fl4->saddr;
194 inet->inet_rcv_saddr = inet->inet_saddr;
196 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
197 /* Reset inherited state */
198 tp->rx_opt.ts_recent = 0;
199 tp->rx_opt.ts_recent_stamp = 0;
200 if (likely(!tp->repair))
204 if (tcp_death_row.sysctl_tw_recycle &&
205 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
206 tcp_fetch_timewait_stamp(sk, &rt->dst);
208 inet->inet_dport = usin->sin_port;
209 inet->inet_daddr = daddr;
213 inet_csk(sk)->icsk_ext_hdr_len = 0;
215 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
217 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
219 /* Socket identity is still unknown (sport may be zero).
220 * However we set state to SYN-SENT and not releasing socket
221 * lock select source port, enter ourselves into the hash tables and
222 * complete initialization after this.
224 tcp_set_state(sk, TCP_SYN_SENT);
225 err = inet_hash_connect(&tcp_death_row, sk);
229 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
230 inet->inet_sport, inet->inet_dport, sk);
236 /* OK, now commit destination to socket. */
237 sk->sk_gso_type = SKB_GSO_TCPV4;
238 sk_setup_caps(sk, &rt->dst);
240 if (!tp->write_seq && likely(!tp->repair))
241 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
246 inet->inet_id = tp->write_seq ^ jiffies;
248 err = tcp_connect(sk);
258 * This unhashes the socket and releases the local port,
261 tcp_set_state(sk, TCP_CLOSE);
263 sk->sk_route_caps = 0;
264 inet->inet_dport = 0;
267 EXPORT_SYMBOL(tcp_v4_connect);
270 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
271 * It can be called through tcp_release_cb() if socket was owned by user
272 * at the time tcp_v4_err() was called to handle ICMP message.
274 static void tcp_v4_mtu_reduced(struct sock *sk)
276 struct dst_entry *dst;
277 struct inet_sock *inet = inet_sk(sk);
278 u32 mtu = tcp_sk(sk)->mtu_info;
280 dst = inet_csk_update_pmtu(sk, mtu);
284 /* Something is about to be wrong... Remember soft error
285 * for the case, if this connection will not able to recover.
287 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
288 sk->sk_err_soft = EMSGSIZE;
292 if (inet->pmtudisc != IP_PMTUDISC_DONT &&
293 ip_sk_accept_pmtu(sk) &&
294 inet_csk(sk)->icsk_pmtu_cookie > mtu) {
295 tcp_sync_mss(sk, mtu);
297 /* Resend the TCP packet because it's
298 * clear that the old packet has been
299 * dropped. This is the new "fast" path mtu
302 tcp_simple_retransmit(sk);
303 } /* else let the usual retransmit timer handle it */
306 static void do_redirect(struct sk_buff *skb, struct sock *sk)
308 struct dst_entry *dst = __sk_dst_check(sk, 0);
311 dst->ops->redirect(dst, sk, skb);
315 * This routine is called by the ICMP module when it gets some
316 * sort of error condition. If err < 0 then the socket should
317 * be closed and the error returned to the user. If err > 0
318 * it's just the icmp type << 8 | icmp code. After adjustment
319 * header points to the first 8 bytes of the tcp header. We need
320 * to find the appropriate port.
322 * The locking strategy used here is very "optimistic". When
323 * someone else accesses the socket the ICMP is just dropped
324 * and for some paths there is no check at all.
325 * A more general error queue to queue errors for later handling
326 * is probably better.
330 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
332 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
333 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
334 struct inet_connection_sock *icsk;
336 struct inet_sock *inet;
337 const int type = icmp_hdr(icmp_skb)->type;
338 const int code = icmp_hdr(icmp_skb)->code;
341 struct request_sock *fastopen;
345 struct net *net = dev_net(icmp_skb->dev);
347 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
348 iph->saddr, th->source, inet_iif(icmp_skb));
350 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
353 if (sk->sk_state == TCP_TIME_WAIT) {
354 inet_twsk_put(inet_twsk(sk));
359 /* If too many ICMPs get dropped on busy
360 * servers this needs to be solved differently.
361 * We do take care of PMTU discovery (RFC1191) special case :
362 * we can receive locally generated ICMP messages while socket is held.
364 if (sock_owned_by_user(sk)) {
365 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
366 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
368 if (sk->sk_state == TCP_CLOSE)
371 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
372 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
378 seq = ntohl(th->seq);
379 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
380 fastopen = tp->fastopen_rsk;
381 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
382 if (sk->sk_state != TCP_LISTEN &&
383 !between(seq, snd_una, tp->snd_nxt)) {
384 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
390 do_redirect(icmp_skb, sk);
392 case ICMP_SOURCE_QUENCH:
393 /* Just silently ignore these. */
395 case ICMP_PARAMETERPROB:
398 case ICMP_DEST_UNREACH:
399 if (code > NR_ICMP_UNREACH)
402 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
403 /* We are not interested in TCP_LISTEN and open_requests
404 * (SYN-ACKs send out by Linux are always <576bytes so
405 * they should go through unfragmented).
407 if (sk->sk_state == TCP_LISTEN)
411 if (!sock_owned_by_user(sk)) {
412 tcp_v4_mtu_reduced(sk);
414 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
420 err = icmp_err_convert[code].errno;
421 /* check if icmp_skb allows revert of backoff
422 * (see draft-zimmermann-tcp-lcd) */
423 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
425 if (seq != tp->snd_una || !icsk->icsk_retransmits ||
426 !icsk->icsk_backoff || fastopen)
429 if (sock_owned_by_user(sk))
432 icsk->icsk_backoff--;
433 inet_csk(sk)->icsk_rto = (tp->srtt_us ? __tcp_set_rto(tp) :
434 TCP_TIMEOUT_INIT) << icsk->icsk_backoff;
437 skb = tcp_write_queue_head(sk);
440 remaining = icsk->icsk_rto - min(icsk->icsk_rto,
441 tcp_time_stamp - TCP_SKB_CB(skb)->when);
444 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
445 remaining, TCP_RTO_MAX);
447 /* RTO revert clocked out retransmission.
448 * Will retransmit now */
449 tcp_retransmit_timer(sk);
453 case ICMP_TIME_EXCEEDED:
460 switch (sk->sk_state) {
461 struct request_sock *req, **prev;
463 if (sock_owned_by_user(sk))
466 req = inet_csk_search_req(sk, &prev, th->dest,
467 iph->daddr, iph->saddr);
471 /* ICMPs are not backlogged, hence we cannot get
472 an established socket here.
476 if (seq != tcp_rsk(req)->snt_isn) {
477 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
482 * Still in SYN_RECV, just remove it silently.
483 * There is no good way to pass the error to the newly
484 * created socket, and POSIX does not want network
485 * errors returned from accept().
487 inet_csk_reqsk_queue_drop(sk, req, prev);
488 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
493 /* Only in fast or simultaneous open. If a fast open socket is
494 * is already accepted it is treated as a connected one below.
496 if (fastopen && fastopen->sk == NULL)
499 if (!sock_owned_by_user(sk)) {
502 sk->sk_error_report(sk);
506 sk->sk_err_soft = err;
511 /* If we've already connected we will keep trying
512 * until we time out, or the user gives up.
514 * rfc1122 4.2.3.9 allows to consider as hard errors
515 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
516 * but it is obsoleted by pmtu discovery).
518 * Note, that in modern internet, where routing is unreliable
519 * and in each dark corner broken firewalls sit, sending random
520 * errors ordered by their masters even this two messages finally lose
521 * their original sense (even Linux sends invalid PORT_UNREACHs)
523 * Now we are in compliance with RFCs.
528 if (!sock_owned_by_user(sk) && inet->recverr) {
530 sk->sk_error_report(sk);
531 } else { /* Only an error on timeout */
532 sk->sk_err_soft = err;
540 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
542 struct tcphdr *th = tcp_hdr(skb);
544 if (skb->ip_summed == CHECKSUM_PARTIAL) {
545 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
546 skb->csum_start = skb_transport_header(skb) - skb->head;
547 skb->csum_offset = offsetof(struct tcphdr, check);
549 th->check = tcp_v4_check(skb->len, saddr, daddr,
556 /* This routine computes an IPv4 TCP checksum. */
557 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
559 const struct inet_sock *inet = inet_sk(sk);
561 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
563 EXPORT_SYMBOL(tcp_v4_send_check);
566 * This routine will send an RST to the other tcp.
568 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
570 * Answer: if a packet caused RST, it is not for a socket
571 * existing in our system, if it is matched to a socket,
572 * it is just duplicate segment or bug in other side's TCP.
573 * So that we build reply only basing on parameters
574 * arrived with segment.
575 * Exception: precedence violation. We do not implement it in any case.
578 static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
580 const struct tcphdr *th = tcp_hdr(skb);
583 #ifdef CONFIG_TCP_MD5SIG
584 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
587 struct ip_reply_arg arg;
588 #ifdef CONFIG_TCP_MD5SIG
589 struct tcp_md5sig_key *key;
590 const __u8 *hash_location = NULL;
591 unsigned char newhash[16];
593 struct sock *sk1 = NULL;
597 /* Never send a reset in response to a reset. */
601 if (skb_rtable(skb)->rt_type != RTN_LOCAL)
604 /* Swap the send and the receive. */
605 memset(&rep, 0, sizeof(rep));
606 rep.th.dest = th->source;
607 rep.th.source = th->dest;
608 rep.th.doff = sizeof(struct tcphdr) / 4;
612 rep.th.seq = th->ack_seq;
615 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
616 skb->len - (th->doff << 2));
619 memset(&arg, 0, sizeof(arg));
620 arg.iov[0].iov_base = (unsigned char *)&rep;
621 arg.iov[0].iov_len = sizeof(rep.th);
623 #ifdef CONFIG_TCP_MD5SIG
624 hash_location = tcp_parse_md5sig_option(th);
625 if (!sk && hash_location) {
627 * active side is lost. Try to find listening socket through
628 * source port, and then find md5 key through listening socket.
629 * we are not loose security here:
630 * Incoming packet is checked with md5 hash with finding key,
631 * no RST generated if md5 hash doesn't match.
633 sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev),
634 &tcp_hashinfo, ip_hdr(skb)->saddr,
635 th->source, ip_hdr(skb)->daddr,
636 ntohs(th->source), inet_iif(skb));
637 /* don't send rst if it can't find key */
641 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
642 &ip_hdr(skb)->saddr, AF_INET);
646 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb);
647 if (genhash || memcmp(hash_location, newhash, 16) != 0)
650 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
656 rep.opt[0] = htonl((TCPOPT_NOP << 24) |
658 (TCPOPT_MD5SIG << 8) |
660 /* Update length and the length the header thinks exists */
661 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
662 rep.th.doff = arg.iov[0].iov_len / 4;
664 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
665 key, ip_hdr(skb)->saddr,
666 ip_hdr(skb)->daddr, &rep.th);
669 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
670 ip_hdr(skb)->saddr, /* XXX */
671 arg.iov[0].iov_len, IPPROTO_TCP, 0);
672 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
673 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
674 /* When socket is gone, all binding information is lost.
675 * routing might fail in this case. No choice here, if we choose to force
676 * input interface, we will misroute in case of asymmetric route.
679 arg.bound_dev_if = sk->sk_bound_dev_if;
681 net = dev_net(skb_dst(skb)->dev);
682 arg.tos = ip_hdr(skb)->tos;
683 ip_send_unicast_reply(net, skb, ip_hdr(skb)->saddr,
684 ip_hdr(skb)->daddr, &arg, arg.iov[0].iov_len);
686 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
687 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
689 #ifdef CONFIG_TCP_MD5SIG
698 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
699 outside socket context is ugly, certainly. What can I do?
702 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
703 u32 win, u32 tsval, u32 tsecr, int oif,
704 struct tcp_md5sig_key *key,
705 int reply_flags, u8 tos)
707 const struct tcphdr *th = tcp_hdr(skb);
710 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
711 #ifdef CONFIG_TCP_MD5SIG
712 + (TCPOLEN_MD5SIG_ALIGNED >> 2)
716 struct ip_reply_arg arg;
717 struct net *net = dev_net(skb_dst(skb)->dev);
719 memset(&rep.th, 0, sizeof(struct tcphdr));
720 memset(&arg, 0, sizeof(arg));
722 arg.iov[0].iov_base = (unsigned char *)&rep;
723 arg.iov[0].iov_len = sizeof(rep.th);
725 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
726 (TCPOPT_TIMESTAMP << 8) |
728 rep.opt[1] = htonl(tsval);
729 rep.opt[2] = htonl(tsecr);
730 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
733 /* Swap the send and the receive. */
734 rep.th.dest = th->source;
735 rep.th.source = th->dest;
736 rep.th.doff = arg.iov[0].iov_len / 4;
737 rep.th.seq = htonl(seq);
738 rep.th.ack_seq = htonl(ack);
740 rep.th.window = htons(win);
742 #ifdef CONFIG_TCP_MD5SIG
744 int offset = (tsecr) ? 3 : 0;
746 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
748 (TCPOPT_MD5SIG << 8) |
750 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
751 rep.th.doff = arg.iov[0].iov_len/4;
753 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
754 key, ip_hdr(skb)->saddr,
755 ip_hdr(skb)->daddr, &rep.th);
758 arg.flags = reply_flags;
759 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
760 ip_hdr(skb)->saddr, /* XXX */
761 arg.iov[0].iov_len, IPPROTO_TCP, 0);
762 arg.csumoffset = offsetof(struct tcphdr, check) / 2;
764 arg.bound_dev_if = oif;
766 ip_send_unicast_reply(net, skb, ip_hdr(skb)->saddr,
767 ip_hdr(skb)->daddr, &arg, arg.iov[0].iov_len);
769 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
772 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
774 struct inet_timewait_sock *tw = inet_twsk(sk);
775 struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
777 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
778 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
779 tcp_time_stamp + tcptw->tw_ts_offset,
782 tcp_twsk_md5_key(tcptw),
783 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
790 static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
791 struct request_sock *req)
793 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
794 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
796 tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
797 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
798 tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
802 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
804 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
809 * Send a SYN-ACK after having received a SYN.
810 * This still operates on a request_sock only, not on a big
813 static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
815 struct request_sock *req,
817 struct tcp_fastopen_cookie *foc)
819 const struct inet_request_sock *ireq = inet_rsk(req);
824 /* First, grab a route. */
825 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
828 skb = tcp_make_synack(sk, dst, req, foc);
831 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
833 skb_set_queue_mapping(skb, queue_mapping);
834 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
837 err = net_xmit_eval(err);
844 * IPv4 request_sock destructor.
846 static void tcp_v4_reqsk_destructor(struct request_sock *req)
848 kfree(inet_rsk(req)->opt);
852 * Return true if a syncookie should be sent
854 bool tcp_syn_flood_action(struct sock *sk,
855 const struct sk_buff *skb,
858 const char *msg = "Dropping request";
859 bool want_cookie = false;
860 struct listen_sock *lopt;
862 #ifdef CONFIG_SYN_COOKIES
863 if (sysctl_tcp_syncookies) {
864 msg = "Sending cookies";
866 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
869 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
871 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
872 if (!lopt->synflood_warned && sysctl_tcp_syncookies != 2) {
873 lopt->synflood_warned = 1;
874 pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
875 proto, ntohs(tcp_hdr(skb)->dest), msg);
879 EXPORT_SYMBOL(tcp_syn_flood_action);
882 * Save and compile IPv4 options into the request_sock if needed.
884 static struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb)
886 const struct ip_options *opt = &(IPCB(skb)->opt);
887 struct ip_options_rcu *dopt = NULL;
889 if (opt && opt->optlen) {
890 int opt_size = sizeof(*dopt) + opt->optlen;
892 dopt = kmalloc(opt_size, GFP_ATOMIC);
894 if (ip_options_echo(&dopt->opt, skb)) {
903 #ifdef CONFIG_TCP_MD5SIG
905 * RFC2385 MD5 checksumming requires a mapping of
906 * IP address->MD5 Key.
907 * We need to maintain these in the sk structure.
910 /* Find the Key structure for an address. */
911 struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
912 const union tcp_md5_addr *addr,
915 struct tcp_sock *tp = tcp_sk(sk);
916 struct tcp_md5sig_key *key;
917 unsigned int size = sizeof(struct in_addr);
918 struct tcp_md5sig_info *md5sig;
920 /* caller either holds rcu_read_lock() or socket lock */
921 md5sig = rcu_dereference_check(tp->md5sig_info,
922 sock_owned_by_user(sk) ||
923 lockdep_is_held(&sk->sk_lock.slock));
926 #if IS_ENABLED(CONFIG_IPV6)
927 if (family == AF_INET6)
928 size = sizeof(struct in6_addr);
930 hlist_for_each_entry_rcu(key, &md5sig->head, node) {
931 if (key->family != family)
933 if (!memcmp(&key->addr, addr, size))
938 EXPORT_SYMBOL(tcp_md5_do_lookup);
940 struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
941 struct sock *addr_sk)
943 union tcp_md5_addr *addr;
945 addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr;
946 return tcp_md5_do_lookup(sk, addr, AF_INET);
948 EXPORT_SYMBOL(tcp_v4_md5_lookup);
950 static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
951 struct request_sock *req)
953 union tcp_md5_addr *addr;
955 addr = (union tcp_md5_addr *)&inet_rsk(req)->ir_rmt_addr;
956 return tcp_md5_do_lookup(sk, addr, AF_INET);
959 /* This can be called on a newly created socket, from other files */
960 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
961 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
963 /* Add Key to the list */
964 struct tcp_md5sig_key *key;
965 struct tcp_sock *tp = tcp_sk(sk);
966 struct tcp_md5sig_info *md5sig;
968 key = tcp_md5_do_lookup(sk, addr, family);
970 /* Pre-existing entry - just update that one. */
971 memcpy(key->key, newkey, newkeylen);
972 key->keylen = newkeylen;
976 md5sig = rcu_dereference_protected(tp->md5sig_info,
977 sock_owned_by_user(sk));
979 md5sig = kmalloc(sizeof(*md5sig), gfp);
983 sk_nocaps_add(sk, NETIF_F_GSO_MASK);
984 INIT_HLIST_HEAD(&md5sig->head);
985 rcu_assign_pointer(tp->md5sig_info, md5sig);
988 key = sock_kmalloc(sk, sizeof(*key), gfp);
991 if (!tcp_alloc_md5sig_pool()) {
992 sock_kfree_s(sk, key, sizeof(*key));
996 memcpy(key->key, newkey, newkeylen);
997 key->keylen = newkeylen;
998 key->family = family;
999 memcpy(&key->addr, addr,
1000 (family == AF_INET6) ? sizeof(struct in6_addr) :
1001 sizeof(struct in_addr));
1002 hlist_add_head_rcu(&key->node, &md5sig->head);
1005 EXPORT_SYMBOL(tcp_md5_do_add);
1007 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
1009 struct tcp_md5sig_key *key;
1011 key = tcp_md5_do_lookup(sk, addr, family);
1014 hlist_del_rcu(&key->node);
1015 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1016 kfree_rcu(key, rcu);
1019 EXPORT_SYMBOL(tcp_md5_do_del);
1021 static void tcp_clear_md5_list(struct sock *sk)
1023 struct tcp_sock *tp = tcp_sk(sk);
1024 struct tcp_md5sig_key *key;
1025 struct hlist_node *n;
1026 struct tcp_md5sig_info *md5sig;
1028 md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
1030 hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
1031 hlist_del_rcu(&key->node);
1032 atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
1033 kfree_rcu(key, rcu);
1037 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
1040 struct tcp_md5sig cmd;
1041 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
1043 if (optlen < sizeof(cmd))
1046 if (copy_from_user(&cmd, optval, sizeof(cmd)))
1049 if (sin->sin_family != AF_INET)
1052 if (!cmd.tcpm_keylen)
1053 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1056 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
1059 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
1060 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
1064 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
1065 __be32 daddr, __be32 saddr, int nbytes)
1067 struct tcp4_pseudohdr *bp;
1068 struct scatterlist sg;
1070 bp = &hp->md5_blk.ip4;
1073 * 1. the TCP pseudo-header (in the order: source IP address,
1074 * destination IP address, zero-padded protocol number, and
1080 bp->protocol = IPPROTO_TCP;
1081 bp->len = cpu_to_be16(nbytes);
1083 sg_init_one(&sg, bp, sizeof(*bp));
1084 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
1087 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
1088 __be32 daddr, __be32 saddr, const struct tcphdr *th)
1090 struct tcp_md5sig_pool *hp;
1091 struct hash_desc *desc;
1093 hp = tcp_get_md5sig_pool();
1095 goto clear_hash_noput;
1096 desc = &hp->md5_desc;
1098 if (crypto_hash_init(desc))
1100 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
1102 if (tcp_md5_hash_header(hp, th))
1104 if (tcp_md5_hash_key(hp, key))
1106 if (crypto_hash_final(desc, md5_hash))
1109 tcp_put_md5sig_pool();
1113 tcp_put_md5sig_pool();
1115 memset(md5_hash, 0, 16);
1119 int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
1120 const struct sock *sk, const struct request_sock *req,
1121 const struct sk_buff *skb)
1123 struct tcp_md5sig_pool *hp;
1124 struct hash_desc *desc;
1125 const struct tcphdr *th = tcp_hdr(skb);
1126 __be32 saddr, daddr;
1129 saddr = inet_sk(sk)->inet_saddr;
1130 daddr = inet_sk(sk)->inet_daddr;
1132 saddr = inet_rsk(req)->ir_loc_addr;
1133 daddr = inet_rsk(req)->ir_rmt_addr;
1135 const struct iphdr *iph = ip_hdr(skb);
1140 hp = tcp_get_md5sig_pool();
1142 goto clear_hash_noput;
1143 desc = &hp->md5_desc;
1145 if (crypto_hash_init(desc))
1148 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
1150 if (tcp_md5_hash_header(hp, th))
1152 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
1154 if (tcp_md5_hash_key(hp, key))
1156 if (crypto_hash_final(desc, md5_hash))
1159 tcp_put_md5sig_pool();
1163 tcp_put_md5sig_pool();
1165 memset(md5_hash, 0, 16);
1168 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1170 static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
1171 const struct sk_buff *skb)
1174 * This gets called for each TCP segment that arrives
1175 * so we want to be efficient.
1176 * We have 3 drop cases:
1177 * o No MD5 hash and one expected.
1178 * o MD5 hash and we're not expecting one.
1179 * o MD5 hash and its wrong.
1181 const __u8 *hash_location = NULL;
1182 struct tcp_md5sig_key *hash_expected;
1183 const struct iphdr *iph = ip_hdr(skb);
1184 const struct tcphdr *th = tcp_hdr(skb);
1186 unsigned char newhash[16];
1188 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
1190 hash_location = tcp_parse_md5sig_option(th);
1192 /* We've parsed the options - do we have a hash? */
1193 if (!hash_expected && !hash_location)
1196 if (hash_expected && !hash_location) {
1197 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1201 if (!hash_expected && hash_location) {
1202 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1206 /* Okay, so this is hash_expected and hash_location -
1207 * so we need to calculate the checksum.
1209 genhash = tcp_v4_md5_hash_skb(newhash,
1213 if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1214 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
1215 &iph->saddr, ntohs(th->source),
1216 &iph->daddr, ntohs(th->dest),
1217 genhash ? " tcp_v4_calc_md5_hash failed"
1224 static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
1229 ret = __tcp_v4_inbound_md5_hash(sk, skb);
1237 static void tcp_v4_init_req(struct request_sock *req, struct sock *sk,
1238 struct sk_buff *skb)
1240 struct inet_request_sock *ireq = inet_rsk(req);
1242 ireq->ir_loc_addr = ip_hdr(skb)->daddr;
1243 ireq->ir_rmt_addr = ip_hdr(skb)->saddr;
1244 ireq->no_srccheck = inet_sk(sk)->transparent;
1245 ireq->opt = tcp_v4_save_options(skb);
1248 static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl,
1249 const struct request_sock *req,
1252 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
1255 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
1264 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
1266 .obj_size = sizeof(struct tcp_request_sock),
1267 .rtx_syn_ack = tcp_rtx_synack,
1268 .send_ack = tcp_v4_reqsk_send_ack,
1269 .destructor = tcp_v4_reqsk_destructor,
1270 .send_reset = tcp_v4_send_reset,
1271 .syn_ack_timeout = tcp_syn_ack_timeout,
1274 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1275 .mss_clamp = TCP_MSS_DEFAULT,
1276 #ifdef CONFIG_TCP_MD5SIG
1277 .md5_lookup = tcp_v4_reqsk_md5_lookup,
1278 .calc_md5_hash = tcp_v4_md5_hash_skb,
1280 .init_req = tcp_v4_init_req,
1281 #ifdef CONFIG_SYN_COOKIES
1282 .cookie_init_seq = cookie_v4_init_sequence,
1284 .route_req = tcp_v4_route_req,
1285 .init_seq = tcp_v4_init_sequence,
1286 .send_synack = tcp_v4_send_synack,
1287 .queue_hash_add = inet_csk_reqsk_queue_hash_add,
1290 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
1292 /* Never answer to SYNs send to broadcast or multicast */
1293 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
1296 return tcp_conn_request(&tcp_request_sock_ops,
1297 &tcp_request_sock_ipv4_ops, sk, skb);
1300 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1303 EXPORT_SYMBOL(tcp_v4_conn_request);
1307 * The three way handshake has completed - we got a valid synack -
1308 * now create the new socket.
1310 struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1311 struct request_sock *req,
1312 struct dst_entry *dst)
1314 struct inet_request_sock *ireq;
1315 struct inet_sock *newinet;
1316 struct tcp_sock *newtp;
1318 #ifdef CONFIG_TCP_MD5SIG
1319 struct tcp_md5sig_key *key;
1321 struct ip_options_rcu *inet_opt;
1323 if (sk_acceptq_is_full(sk))
1326 newsk = tcp_create_openreq_child(sk, req, skb);
1330 newsk->sk_gso_type = SKB_GSO_TCPV4;
1331 inet_sk_rx_dst_set(newsk, skb);
1333 newtp = tcp_sk(newsk);
1334 newinet = inet_sk(newsk);
1335 ireq = inet_rsk(req);
1336 newinet->inet_daddr = ireq->ir_rmt_addr;
1337 newinet->inet_rcv_saddr = ireq->ir_loc_addr;
1338 newinet->inet_saddr = ireq->ir_loc_addr;
1339 inet_opt = ireq->opt;
1340 rcu_assign_pointer(newinet->inet_opt, inet_opt);
1342 newinet->mc_index = inet_iif(skb);
1343 newinet->mc_ttl = ip_hdr(skb)->ttl;
1344 newinet->rcv_tos = ip_hdr(skb)->tos;
1345 inet_csk(newsk)->icsk_ext_hdr_len = 0;
1346 inet_set_txhash(newsk);
1348 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
1349 newinet->inet_id = newtp->write_seq ^ jiffies;
1352 dst = inet_csk_route_child_sock(sk, newsk, req);
1356 /* syncookie case : see end of cookie_v4_check() */
1358 sk_setup_caps(newsk, dst);
1360 tcp_sync_mss(newsk, dst_mtu(dst));
1361 newtp->advmss = dst_metric_advmss(dst);
1362 if (tcp_sk(sk)->rx_opt.user_mss &&
1363 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
1364 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
1366 tcp_initialize_rcv_mss(newsk);
1368 #ifdef CONFIG_TCP_MD5SIG
1369 /* Copy over the MD5 key from the original socket */
1370 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
1374 * We're using one, so create a matching key
1375 * on the newsk structure. If we fail to get
1376 * memory, then we end up not copying the key
1379 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
1380 AF_INET, key->key, key->keylen, GFP_ATOMIC);
1381 sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1385 if (__inet_inherit_port(sk, newsk) < 0)
1387 __inet_hash_nolisten(newsk, NULL);
1392 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1396 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
1399 inet_csk_prepare_forced_close(newsk);
1403 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
1405 static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
1407 struct tcphdr *th = tcp_hdr(skb);
1408 const struct iphdr *iph = ip_hdr(skb);
1410 struct request_sock **prev;
1411 /* Find possible connection requests. */
1412 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
1413 iph->saddr, iph->daddr);
1415 return tcp_check_req(sk, skb, req, prev, false);
1417 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1418 th->source, iph->daddr, th->dest, inet_iif(skb));
1421 if (nsk->sk_state != TCP_TIME_WAIT) {
1425 inet_twsk_put(inet_twsk(nsk));
1429 #ifdef CONFIG_SYN_COOKIES
1431 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
1436 /* The socket must have it's spinlock held when we get
1439 * We have a potential double-lock case here, so even when
1440 * doing backlog processing we use the BH locking scheme.
1441 * This is because we cannot sleep with the original spinlock
1444 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
1448 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1449 struct dst_entry *dst = sk->sk_rx_dst;
1451 sock_rps_save_rxhash(sk, skb);
1453 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1454 dst->ops->check(dst, 0) == NULL) {
1456 sk->sk_rx_dst = NULL;
1459 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
1463 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
1466 if (sk->sk_state == TCP_LISTEN) {
1467 struct sock *nsk = tcp_v4_hnd_req(sk, skb);
1472 sock_rps_save_rxhash(nsk, skb);
1473 if (tcp_child_process(sk, nsk, skb)) {
1480 sock_rps_save_rxhash(sk, skb);
1482 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1489 tcp_v4_send_reset(rsk, skb);
1492 /* Be careful here. If this function gets more complicated and
1493 * gcc suffers from register pressure on the x86, sk (in %ebx)
1494 * might be destroyed here. This current version compiles correctly,
1495 * but you have been warned.
1500 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1501 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
1504 EXPORT_SYMBOL(tcp_v4_do_rcv);
1506 void tcp_v4_early_demux(struct sk_buff *skb)
1508 const struct iphdr *iph;
1509 const struct tcphdr *th;
1512 if (skb->pkt_type != PACKET_HOST)
1515 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1521 if (th->doff < sizeof(struct tcphdr) / 4)
1524 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
1525 iph->saddr, th->source,
1526 iph->daddr, ntohs(th->dest),
1530 skb->destructor = sock_edemux;
1531 if (sk->sk_state != TCP_TIME_WAIT) {
1532 struct dst_entry *dst = sk->sk_rx_dst;
1535 dst = dst_check(dst, 0);
1537 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1538 skb_dst_set_noref(skb, dst);
1543 /* Packet is added to VJ-style prequeue for processing in process
1544 * context, if a reader task is waiting. Apparently, this exciting
1545 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
1546 * failed somewhere. Latency? Burstiness? Well, at least now we will
1547 * see, why it failed. 8)8) --ANK
1550 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
1552 struct tcp_sock *tp = tcp_sk(sk);
1554 if (sysctl_tcp_low_latency || !tp->ucopy.task)
1557 if (skb->len <= tcp_hdrlen(skb) &&
1558 skb_queue_len(&tp->ucopy.prequeue) == 0)
1562 __skb_queue_tail(&tp->ucopy.prequeue, skb);
1563 tp->ucopy.memory += skb->truesize;
1564 if (tp->ucopy.memory > sk->sk_rcvbuf) {
1565 struct sk_buff *skb1;
1567 BUG_ON(sock_owned_by_user(sk));
1569 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
1570 sk_backlog_rcv(sk, skb1);
1571 NET_INC_STATS_BH(sock_net(sk),
1572 LINUX_MIB_TCPPREQUEUEDROPPED);
1575 tp->ucopy.memory = 0;
1576 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
1577 wake_up_interruptible_sync_poll(sk_sleep(sk),
1578 POLLIN | POLLRDNORM | POLLRDBAND);
1579 if (!inet_csk_ack_scheduled(sk))
1580 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
1581 (3 * tcp_rto_min(sk)) / 4,
1586 EXPORT_SYMBOL(tcp_prequeue);
1592 int tcp_v4_rcv(struct sk_buff *skb)
1594 const struct iphdr *iph;
1595 const struct tcphdr *th;
1598 struct net *net = dev_net(skb->dev);
1600 if (skb->pkt_type != PACKET_HOST)
1603 /* Count it even if it's bad */
1604 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
1606 if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
1611 if (th->doff < sizeof(struct tcphdr) / 4)
1613 if (!pskb_may_pull(skb, th->doff * 4))
1616 /* An explanation is required here, I think.
1617 * Packet length and doff are validated by header prediction,
1618 * provided case of th->doff==0 is eliminated.
1619 * So, we defer the checks. */
1621 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1626 TCP_SKB_CB(skb)->seq = ntohl(th->seq);
1627 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
1628 skb->len - th->doff * 4);
1629 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
1630 TCP_SKB_CB(skb)->when = 0;
1631 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
1632 TCP_SKB_CB(skb)->sacked = 0;
1634 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
1639 if (sk->sk_state == TCP_TIME_WAIT)
1642 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
1643 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1644 goto discard_and_relse;
1647 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1648 goto discard_and_relse;
1650 #ifdef CONFIG_TCP_MD5SIG
1652 * We really want to reject the packet as early as possible
1654 * o We're expecting an MD5'd packet and this is no MD5 tcp option
1655 * o There is an MD5 option and we're not expecting one
1657 if (tcp_v4_inbound_md5_hash(sk, skb))
1658 goto discard_and_relse;
1663 if (sk_filter(sk, skb))
1664 goto discard_and_relse;
1666 sk_mark_napi_id(sk, skb);
1669 bh_lock_sock_nested(sk);
1671 if (!sock_owned_by_user(sk)) {
1672 #ifdef CONFIG_NET_DMA
1673 struct tcp_sock *tp = tcp_sk(sk);
1674 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1675 tp->ucopy.dma_chan = net_dma_find_channel();
1676 if (tp->ucopy.dma_chan)
1677 ret = tcp_v4_do_rcv(sk, skb);
1681 if (!tcp_prequeue(sk, skb))
1682 ret = tcp_v4_do_rcv(sk, skb);
1684 } else if (unlikely(sk_add_backlog(sk, skb,
1685 sk->sk_rcvbuf + sk->sk_sndbuf))) {
1687 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
1688 goto discard_and_relse;
1697 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1700 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1702 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
1704 TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1706 tcp_v4_send_reset(NULL, skb);
1710 /* Discard frame. */
1719 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1720 inet_twsk_put(inet_twsk(sk));
1724 if (skb->len < (th->doff << 2)) {
1725 inet_twsk_put(inet_twsk(sk));
1728 if (tcp_checksum_complete(skb)) {
1729 inet_twsk_put(inet_twsk(sk));
1732 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
1734 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1736 iph->saddr, th->source,
1737 iph->daddr, th->dest,
1740 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
1741 inet_twsk_put(inet_twsk(sk));
1745 /* Fall through to ACK */
1748 tcp_v4_timewait_ack(sk, skb);
1752 case TCP_TW_SUCCESS:;
1757 static struct timewait_sock_ops tcp_timewait_sock_ops = {
1758 .twsk_obj_size = sizeof(struct tcp_timewait_sock),
1759 .twsk_unique = tcp_twsk_unique,
1760 .twsk_destructor= tcp_twsk_destructor,
1763 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
1765 struct dst_entry *dst = skb_dst(skb);
1768 sk->sk_rx_dst = dst;
1769 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
1771 EXPORT_SYMBOL(inet_sk_rx_dst_set);
1773 const struct inet_connection_sock_af_ops ipv4_specific = {
1774 .queue_xmit = ip_queue_xmit,
1775 .send_check = tcp_v4_send_check,
1776 .rebuild_header = inet_sk_rebuild_header,
1777 .sk_rx_dst_set = inet_sk_rx_dst_set,
1778 .conn_request = tcp_v4_conn_request,
1779 .syn_recv_sock = tcp_v4_syn_recv_sock,
1780 .net_header_len = sizeof(struct iphdr),
1781 .setsockopt = ip_setsockopt,
1782 .getsockopt = ip_getsockopt,
1783 .addr2sockaddr = inet_csk_addr2sockaddr,
1784 .sockaddr_len = sizeof(struct sockaddr_in),
1785 .bind_conflict = inet_csk_bind_conflict,
1786 #ifdef CONFIG_COMPAT
1787 .compat_setsockopt = compat_ip_setsockopt,
1788 .compat_getsockopt = compat_ip_getsockopt,
1791 EXPORT_SYMBOL(ipv4_specific);
1793 #ifdef CONFIG_TCP_MD5SIG
1794 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1795 .md5_lookup = tcp_v4_md5_lookup,
1796 .calc_md5_hash = tcp_v4_md5_hash_skb,
1797 .md5_parse = tcp_v4_parse_md5_keys,
1801 /* NOTE: A lot of things set to zero explicitly by call to
1802 * sk_alloc() so need not be done here.
1804 static int tcp_v4_init_sock(struct sock *sk)
1806 struct inet_connection_sock *icsk = inet_csk(sk);
1810 icsk->icsk_af_ops = &ipv4_specific;
1812 #ifdef CONFIG_TCP_MD5SIG
1813 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1819 void tcp_v4_destroy_sock(struct sock *sk)
1821 struct tcp_sock *tp = tcp_sk(sk);
1823 tcp_clear_xmit_timers(sk);
1825 tcp_cleanup_congestion_control(sk);
1827 /* Cleanup up the write buffer. */
1828 tcp_write_queue_purge(sk);
1830 /* Cleans up our, hopefully empty, out_of_order_queue. */
1831 __skb_queue_purge(&tp->out_of_order_queue);
1833 #ifdef CONFIG_TCP_MD5SIG
1834 /* Clean up the MD5 key list, if any */
1835 if (tp->md5sig_info) {
1836 tcp_clear_md5_list(sk);
1837 kfree_rcu(tp->md5sig_info, rcu);
1838 tp->md5sig_info = NULL;
1842 #ifdef CONFIG_NET_DMA
1843 /* Cleans up our sk_async_wait_queue */
1844 __skb_queue_purge(&sk->sk_async_wait_queue);
1847 /* Clean prequeue, it must be empty really */
1848 __skb_queue_purge(&tp->ucopy.prequeue);
1850 /* Clean up a referenced TCP bind bucket. */
1851 if (inet_csk(sk)->icsk_bind_hash)
1854 BUG_ON(tp->fastopen_rsk != NULL);
1856 /* If socket is aborted during connect operation */
1857 tcp_free_fastopen_req(tp);
1859 sk_sockets_allocated_dec(sk);
1860 sock_release_memcg(sk);
1862 EXPORT_SYMBOL(tcp_v4_destroy_sock);
1864 #ifdef CONFIG_PROC_FS
1865 /* Proc filesystem TCP sock list dumping. */
1868 * Get next listener socket follow cur. If cur is NULL, get first socket
1869 * starting from bucket given in st->bucket; when st->bucket is zero the
1870 * very first socket in the hash table is returned.
1872 static void *listening_get_next(struct seq_file *seq, void *cur)
1874 struct inet_connection_sock *icsk;
1875 struct hlist_nulls_node *node;
1876 struct sock *sk = cur;
1877 struct inet_listen_hashbucket *ilb;
1878 struct tcp_iter_state *st = seq->private;
1879 struct net *net = seq_file_net(seq);
1882 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1883 spin_lock_bh(&ilb->lock);
1884 sk = sk_nulls_head(&ilb->head);
1888 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1892 if (st->state == TCP_SEQ_STATE_OPENREQ) {
1893 struct request_sock *req = cur;
1895 icsk = inet_csk(st->syn_wait_sk);
1899 if (req->rsk_ops->family == st->family) {
1905 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
1908 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
1910 sk = sk_nulls_next(st->syn_wait_sk);
1911 st->state = TCP_SEQ_STATE_LISTENING;
1912 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1914 icsk = inet_csk(sk);
1915 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1916 if (reqsk_queue_len(&icsk->icsk_accept_queue))
1918 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1919 sk = sk_nulls_next(sk);
1922 sk_nulls_for_each_from(sk, node) {
1923 if (!net_eq(sock_net(sk), net))
1925 if (sk->sk_family == st->family) {
1929 icsk = inet_csk(sk);
1930 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1931 if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
1933 st->uid = sock_i_uid(sk);
1934 st->syn_wait_sk = sk;
1935 st->state = TCP_SEQ_STATE_OPENREQ;
1939 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1941 spin_unlock_bh(&ilb->lock);
1943 if (++st->bucket < INET_LHTABLE_SIZE) {
1944 ilb = &tcp_hashinfo.listening_hash[st->bucket];
1945 spin_lock_bh(&ilb->lock);
1946 sk = sk_nulls_head(&ilb->head);
1954 static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
1956 struct tcp_iter_state *st = seq->private;
1961 rc = listening_get_next(seq, NULL);
1963 while (rc && *pos) {
1964 rc = listening_get_next(seq, rc);
1970 static inline bool empty_bucket(const struct tcp_iter_state *st)
1972 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1976 * Get first established socket starting from bucket given in st->bucket.
1977 * If st->bucket is zero, the very first socket in the hash is returned.
1979 static void *established_get_first(struct seq_file *seq)
1981 struct tcp_iter_state *st = seq->private;
1982 struct net *net = seq_file_net(seq);
1986 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
1988 struct hlist_nulls_node *node;
1989 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
1991 /* Lockless fast path for the common case of empty buckets */
1992 if (empty_bucket(st))
1996 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1997 if (sk->sk_family != st->family ||
1998 !net_eq(sock_net(sk), net)) {
2004 spin_unlock_bh(lock);
2010 static void *established_get_next(struct seq_file *seq, void *cur)
2012 struct sock *sk = cur;
2013 struct hlist_nulls_node *node;
2014 struct tcp_iter_state *st = seq->private;
2015 struct net *net = seq_file_net(seq);
2020 sk = sk_nulls_next(sk);
2022 sk_nulls_for_each_from(sk, node) {
2023 if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
2027 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2029 return established_get_first(seq);
2032 static void *established_get_idx(struct seq_file *seq, loff_t pos)
2034 struct tcp_iter_state *st = seq->private;
2038 rc = established_get_first(seq);
2041 rc = established_get_next(seq, rc);
2047 static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
2050 struct tcp_iter_state *st = seq->private;
2052 st->state = TCP_SEQ_STATE_LISTENING;
2053 rc = listening_get_idx(seq, &pos);
2056 st->state = TCP_SEQ_STATE_ESTABLISHED;
2057 rc = established_get_idx(seq, pos);
2063 static void *tcp_seek_last_pos(struct seq_file *seq)
2065 struct tcp_iter_state *st = seq->private;
2066 int offset = st->offset;
2067 int orig_num = st->num;
2070 switch (st->state) {
2071 case TCP_SEQ_STATE_OPENREQ:
2072 case TCP_SEQ_STATE_LISTENING:
2073 if (st->bucket >= INET_LHTABLE_SIZE)
2075 st->state = TCP_SEQ_STATE_LISTENING;
2076 rc = listening_get_next(seq, NULL);
2077 while (offset-- && rc)
2078 rc = listening_get_next(seq, rc);
2082 st->state = TCP_SEQ_STATE_ESTABLISHED;
2084 case TCP_SEQ_STATE_ESTABLISHED:
2085 if (st->bucket > tcp_hashinfo.ehash_mask)
2087 rc = established_get_first(seq);
2088 while (offset-- && rc)
2089 rc = established_get_next(seq, rc);
2097 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
2099 struct tcp_iter_state *st = seq->private;
2102 if (*pos && *pos == st->last_pos) {
2103 rc = tcp_seek_last_pos(seq);
2108 st->state = TCP_SEQ_STATE_LISTENING;
2112 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2115 st->last_pos = *pos;
2119 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2121 struct tcp_iter_state *st = seq->private;
2124 if (v == SEQ_START_TOKEN) {
2125 rc = tcp_get_idx(seq, 0);
2129 switch (st->state) {
2130 case TCP_SEQ_STATE_OPENREQ:
2131 case TCP_SEQ_STATE_LISTENING:
2132 rc = listening_get_next(seq, v);
2134 st->state = TCP_SEQ_STATE_ESTABLISHED;
2137 rc = established_get_first(seq);
2140 case TCP_SEQ_STATE_ESTABLISHED:
2141 rc = established_get_next(seq, v);
2146 st->last_pos = *pos;
2150 static void tcp_seq_stop(struct seq_file *seq, void *v)
2152 struct tcp_iter_state *st = seq->private;
2154 switch (st->state) {
2155 case TCP_SEQ_STATE_OPENREQ:
2157 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2158 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
2160 case TCP_SEQ_STATE_LISTENING:
2161 if (v != SEQ_START_TOKEN)
2162 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
2164 case TCP_SEQ_STATE_ESTABLISHED:
2166 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2171 int tcp_seq_open(struct inode *inode, struct file *file)
2173 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
2174 struct tcp_iter_state *s;
2177 err = seq_open_net(inode, file, &afinfo->seq_ops,
2178 sizeof(struct tcp_iter_state));
2182 s = ((struct seq_file *)file->private_data)->private;
2183 s->family = afinfo->family;
2187 EXPORT_SYMBOL(tcp_seq_open);
2189 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
2192 struct proc_dir_entry *p;
2194 afinfo->seq_ops.start = tcp_seq_start;
2195 afinfo->seq_ops.next = tcp_seq_next;
2196 afinfo->seq_ops.stop = tcp_seq_stop;
2198 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2199 afinfo->seq_fops, afinfo);
2204 EXPORT_SYMBOL(tcp_proc_register);
2206 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
2208 remove_proc_entry(afinfo->name, net->proc_net);
2210 EXPORT_SYMBOL(tcp_proc_unregister);
2212 static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2213 struct seq_file *f, int i, kuid_t uid)
2215 const struct inet_request_sock *ireq = inet_rsk(req);
2216 long delta = req->expires - jiffies;
2218 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2219 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
2222 ntohs(inet_sk(sk)->inet_sport),
2224 ntohs(ireq->ir_rmt_port),
2226 0, 0, /* could print option size, but that is af dependent. */
2227 1, /* timers active (only the expire timer) */
2228 jiffies_delta_to_clock_t(delta),
2230 from_kuid_munged(seq_user_ns(f), uid),
2231 0, /* non standard timer */
2232 0, /* open_requests have no inode */
2233 atomic_read(&sk->sk_refcnt),
2237 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
2240 unsigned long timer_expires;
2241 const struct tcp_sock *tp = tcp_sk(sk);
2242 const struct inet_connection_sock *icsk = inet_csk(sk);
2243 const struct inet_sock *inet = inet_sk(sk);
2244 struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
2245 __be32 dest = inet->inet_daddr;
2246 __be32 src = inet->inet_rcv_saddr;
2247 __u16 destp = ntohs(inet->inet_dport);
2248 __u16 srcp = ntohs(inet->inet_sport);
2251 if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
2252 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
2253 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
2255 timer_expires = icsk->icsk_timeout;
2256 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
2258 timer_expires = icsk->icsk_timeout;
2259 } else if (timer_pending(&sk->sk_timer)) {
2261 timer_expires = sk->sk_timer.expires;
2264 timer_expires = jiffies;
2267 if (sk->sk_state == TCP_LISTEN)
2268 rx_queue = sk->sk_ack_backlog;
2271 * because we dont lock socket, we might find a transient negative value
2273 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
2275 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2276 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2277 i, src, srcp, dest, destp, sk->sk_state,
2278 tp->write_seq - tp->snd_una,
2281 jiffies_delta_to_clock_t(timer_expires - jiffies),
2282 icsk->icsk_retransmits,
2283 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2284 icsk->icsk_probes_out,
2286 atomic_read(&sk->sk_refcnt), sk,
2287 jiffies_to_clock_t(icsk->icsk_rto),
2288 jiffies_to_clock_t(icsk->icsk_ack.ato),
2289 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
2291 sk->sk_state == TCP_LISTEN ?
2292 (fastopenq ? fastopenq->max_qlen : 0) :
2293 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
2296 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2297 struct seq_file *f, int i)
2301 s32 delta = tw->tw_ttd - inet_tw_time_stamp();
2303 dest = tw->tw_daddr;
2304 src = tw->tw_rcv_saddr;
2305 destp = ntohs(tw->tw_dport);
2306 srcp = ntohs(tw->tw_sport);
2308 seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2309 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
2310 i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2311 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2312 atomic_read(&tw->tw_refcnt), tw);
2317 static int tcp4_seq_show(struct seq_file *seq, void *v)
2319 struct tcp_iter_state *st;
2320 struct sock *sk = v;
2322 seq_setwidth(seq, TMPSZ - 1);
2323 if (v == SEQ_START_TOKEN) {
2324 seq_puts(seq, " sl local_address rem_address st tx_queue "
2325 "rx_queue tr tm->when retrnsmt uid timeout "
2331 switch (st->state) {
2332 case TCP_SEQ_STATE_LISTENING:
2333 case TCP_SEQ_STATE_ESTABLISHED:
2334 if (sk->sk_state == TCP_TIME_WAIT)
2335 get_timewait4_sock(v, seq, st->num);
2337 get_tcp4_sock(v, seq, st->num);
2339 case TCP_SEQ_STATE_OPENREQ:
2340 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid);
2348 static const struct file_operations tcp_afinfo_seq_fops = {
2349 .owner = THIS_MODULE,
2350 .open = tcp_seq_open,
2352 .llseek = seq_lseek,
2353 .release = seq_release_net
2356 static struct tcp_seq_afinfo tcp4_seq_afinfo = {
2359 .seq_fops = &tcp_afinfo_seq_fops,
2361 .show = tcp4_seq_show,
2365 static int __net_init tcp4_proc_init_net(struct net *net)
2367 return tcp_proc_register(net, &tcp4_seq_afinfo);
2370 static void __net_exit tcp4_proc_exit_net(struct net *net)
2372 tcp_proc_unregister(net, &tcp4_seq_afinfo);
2375 static struct pernet_operations tcp4_net_ops = {
2376 .init = tcp4_proc_init_net,
2377 .exit = tcp4_proc_exit_net,
2380 int __init tcp4_proc_init(void)
2382 return register_pernet_subsys(&tcp4_net_ops);
2385 void tcp4_proc_exit(void)
2387 unregister_pernet_subsys(&tcp4_net_ops);
2389 #endif /* CONFIG_PROC_FS */
2391 struct proto tcp_prot = {
2393 .owner = THIS_MODULE,
2395 .connect = tcp_v4_connect,
2396 .disconnect = tcp_disconnect,
2397 .accept = inet_csk_accept,
2399 .init = tcp_v4_init_sock,
2400 .destroy = tcp_v4_destroy_sock,
2401 .shutdown = tcp_shutdown,
2402 .setsockopt = tcp_setsockopt,
2403 .getsockopt = tcp_getsockopt,
2404 .recvmsg = tcp_recvmsg,
2405 .sendmsg = tcp_sendmsg,
2406 .sendpage = tcp_sendpage,
2407 .backlog_rcv = tcp_v4_do_rcv,
2408 .release_cb = tcp_release_cb,
2409 .mtu_reduced = tcp_v4_mtu_reduced,
2411 .unhash = inet_unhash,
2412 .get_port = inet_csk_get_port,
2413 .enter_memory_pressure = tcp_enter_memory_pressure,
2414 .stream_memory_free = tcp_stream_memory_free,
2415 .sockets_allocated = &tcp_sockets_allocated,
2416 .orphan_count = &tcp_orphan_count,
2417 .memory_allocated = &tcp_memory_allocated,
2418 .memory_pressure = &tcp_memory_pressure,
2419 .sysctl_mem = sysctl_tcp_mem,
2420 .sysctl_wmem = sysctl_tcp_wmem,
2421 .sysctl_rmem = sysctl_tcp_rmem,
2422 .max_header = MAX_TCP_HEADER,
2423 .obj_size = sizeof(struct tcp_sock),
2424 .slab_flags = SLAB_DESTROY_BY_RCU,
2425 .twsk_prot = &tcp_timewait_sock_ops,
2426 .rsk_prot = &tcp_request_sock_ops,
2427 .h.hashinfo = &tcp_hashinfo,
2428 .no_autobind = true,
2429 #ifdef CONFIG_COMPAT
2430 .compat_setsockopt = compat_tcp_setsockopt,
2431 .compat_getsockopt = compat_tcp_getsockopt,
2433 #ifdef CONFIG_MEMCG_KMEM
2434 .init_cgroup = tcp_init_cgroup,
2435 .destroy_cgroup = tcp_destroy_cgroup,
2436 .proto_cgroup = tcp_proto_cgroup,
2439 EXPORT_SYMBOL(tcp_prot);
2441 static int __net_init tcp_sk_init(struct net *net)
2443 net->ipv4.sysctl_tcp_ecn = 2;
2447 static void __net_exit tcp_sk_exit(struct net *net)
2451 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
2453 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2456 static struct pernet_operations __net_initdata tcp_sk_ops = {
2457 .init = tcp_sk_init,
2458 .exit = tcp_sk_exit,
2459 .exit_batch = tcp_sk_exit_batch,
2462 void __init tcp_v4_init(void)
2464 inet_hashinfo_init(&tcp_hashinfo);
2465 if (register_pernet_subsys(&tcp_sk_ops))
2466 panic("Failed to create the TCP control socket.\n");